2003 Arctic Cat ATVs from 250cc to 500cc Service Manual, Page 369Get this manual
19Place the chain tensioner into position and secure with the cap screw and washer
20Remove the cap screw from the end of the chain tensioner; then using flat -blade screwdriver, rotate the adjuster screw inside the tensioner clockwise until the screw bottoms
22Using flat-blade screwdriver, rotate the adjuster screw inside the tensioner counterclockwise until all tension is released; then install the cap screw into the end of the chain tensioner